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The Symmetry I-9 API manages employers, employees, form submissions, and E-Verify cases for Form I-9 completion. The endpoint reference in this section is generated from the I-9 OpenAPI specification.

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Environments and base URLs

Symmetry I-9 runs in a single production environment. There is no separate staging or sandbox environment.
To test your integration safely, register a dedicated test employer in production and point its webhook and postback URLs at your own test endpoints. See Testing your setup with employer-level isolation.

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Authentication

Make a request to the /authentication endpoint using your API key. This returns a valid access token, which you then send on every other request.
Access token versus API keyYour access token is not the same as your API key. The API key is used for initial authentication to obtain an access token from the /authentication endpoint. The access token is then used to authorize and interact with the other I-9 API endpoints securely.

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Try it live with Swagger

For interactive, authenticated calls against the running service, use the hosted Swagger UI. It mirrors the endpoints in the API reference and lets you execute real requests.

Production Swagger

Live API explorer for every I-9 endpoint.

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Step 1: Generate an access token

Make a request to the /authentication endpoint using your API key. This returns a valid access token.

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Step 2: Authorize in Swagger

  • Select the Authorize button on the right side of the Swagger UI.
  • Paste your access token into the dialog box.
  • Select Authorize.
Once authorized, an unlocked icon appears next to each endpoint, indicating that you can now send requests.

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Step 3: Try out endpoints

  • Select an endpoint.
  • Select Try it out.
  • Select Execute.
Swagger displays the API’s response.

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Next steps

Postman

Download the I-9 Postman collection and environment directly from the API.

Endpoints

Full reference for every employer, employee, admin, and E-Verify endpoint.